Questions were being asked tonight about the seaworthiness of a cruise liner that had to be evacuated as it began to sink after hitting an iceberg in the Antarctic Ocean.

Two inspections earlier this year found 11 deficiencies with the ship, called the M/S Explorer, which is sinking near the South Shetland Islands, south of Argentina.

All 154 passengers and crew abandoned the 2,400-tonne vessel, which is listing 30 degrees to starboard, and were transferred to a rescue vessel, the Nord Norge, via life rafts.

One maritime expert said the incident raised concerns about the growing trend to run cruises "in increasingly exotic and remote locations, often in inherently dangerous conditions".

"There are many questions about the suitability of some ships to operate in such potentially adverse conditions, often well away from adequate search-and-rescue cover," said Mark Dickinson, assistant general secretary of the maritime union Nautilus UK.

Although all the crew and passengers were evacuated safely, Dickinson raised concern that the ship had old-style open lifeboats despite sailing in Antarctic waters.

" The vessel was not breaking any rules by having such lifeboats rather than the more-closed newer ones. But you have to question whether a vessel visiting icy waters with elderly passengers aboard was as equipped as it might have been."

An inspection by the British Maritime and Coastguard Agency (MCA) in Greenock, Scotland, in May this year found the MS Explorer had five deficiencies, including missing search and rescue plans and lifeboat maintenance problems.

The ship was held in port until these safety concerns were addressed. An MCA spokesman, Mark Clarke, said: "These were not huge problems and were all rectified before the vessel sailed. It would not have been allowed to depart if everything had not been sorted out."

It is understood that Chilean port state control inspectors also found six deficiencies during an inspection of the ship in Puerto Natales in March. These included two related to safety of navigation matters.

Classification society Det Norske Veritas issued a passenger safety certificate for the vessel on October 21, the MCA said.

Susan Hayes of Gap Adventures, which owns the stricken vessel, said: "The ship ran into some ice. It was submerged ice and the result was a hole about the size of a fist in the side of the hull so it began taking on water ... but quite slowly.

"The passengers are absolutely fine. They're all accounted for, no injuries whatsoever."

Arnvid Hansen, captain of the Nord Norge, which rescued all those on board the stricken liner, told Sky News: "We were the first on the scene. Most of the passengers had thermal suits and lifejackets on. Everybody appeared to be in good condition."

Coastguards in Falmouth, Cornwall, along with services in Virginia, US, and Ushuaia, Argentina, are assisting with the rescue operation.

The MS Explorer was carrying a total of 100 passengers and 54 crew. As well as those from Britain, the passengers included two Argentines, 10 Australians, two Belgians, 12 Canadians, one Chinese, three Danes, 17 Dutch, one French, one German, two from Hong Kong, four Irish, one Japanese, four Swiss, 14 Americans, one Colombian and one Swede.

A Chilean air force commander, Raul Jorquera, who is based at an airbase on King George Island, said those rescued would be flown to Punta Arenas at the southernmost tip of Chile tomorrow.

The Explorer, built in 1969, is one of the best-known specialist cruise ships in the world. It pioneered the tourist market for Antarctic tours, taking in South Atlantic highlights such as the Falkland Islands and South Georgia.

The ship was on a 19-day circuit of Antarctica and the Falklands that included observing penguins, whales and other regional wildlife. Its standard two-week trip around the Antarctic costs around £4,000 per cabin.